ForthWrite

ForthWrite is an AI email writing assistant that learns your writing style from your real sent mail and uses it to generate drafts that sound like you wrote them.

It works natively inside Gmail and Outlook via a Chrome extension. Key capabilities include:

- Voice matching: captures your tone, rhythm, and sign-offs from sent history

- Auto-draft: generates replies as emails arrive, before you open your inbox

- Recipient-aware drafts: adapts style based on who you are writing to

- Prompt Lab: version-control and A/B test your persona prompt against real sent mail

- BYOK support: bring your own API key for Claude, OpenAI, Grok, Mistral, and others

- Performance analytics: tracks acceptance rate, voice alignment score, and time saved

- Data portability: full training data export and one-click wipe

Free tier includes 10 drafts per week with no credit card required. Paid plans start at $18 per month and include unlimited drafts, custom persona prompts, and auto-draft.